The present invention relates to the field of fiber optics. It concerns an optical plug-in connector for simultaneously connecting a plurality of fiber-optic cables according to the precharacterizing clause of claim 1 and also an insert for such a plug-in connector.
Such a plug-in connector is known for example from the printed publications U.S. Pat. No. 5,436,993 or U.S. Pat. No. 5,590,229.
On account of their high transmission capacity and their immanent interference immunity, fiber-optic networks are being used increasingly in various technical areas, such as for example the communications infrastructure of buildings and the like. The reliable and easy-to-handle, releasable connection between different fiber-optic cables by means of optical plug-in connectors is of decisive significance in this respect. Since the complexity of the communication tasks is constantly growing, it is required for an ever-increasing number of cables to be connected to one another and, correspondingly, for an ever-increasing number of such plug-in connections to be accommodated in a confined space. This is the case in particular when, for reasons of capacity, a plurality of parallel cables are used instead of one cable and correspondingly have to be simultaneously connected.
A very simple method of changing over from a single (simplex) plug-in connection to a double (duplex) plug-in connection is to combine two conventional simplex plug-in connectors with suitable connecting means to form a duplex plug-in connector. Examples of such a solution are disclosed in U.S. Pat. No. 5,528,712 or U.S. Pat. No. 5,343,547. Although such a duplex plug-in connector has the advantage that it can be constructed in a very simple way from already existing simplex plug-in connectors, it is disadvantageous that, with plug-in connectors of this type, no space is saved, instead it just being ensured that two otherwise unchanged simplex plug-in connectors are actuated simultaneously.
On the other hand, there have already been a number of proposals for very compact, space-saving optical multiple plug-in connectors in which the fibers of a plurality of fiber-optic cables or multifiber cables end in a single ferrule of a plug-in connector and are correspondingly connected simultaneously when the plug-in connector is actuated. In U.S. Pat. No. 5,727,101, the one cylindrical ferrule of the plug-in connector contains two central bores for receiving two optical fibers. In U.S. Pat. No. 5,799,122 there is provided a flat ferrule of rectangular cross section, in which a plurality of bores for receiving fiber ends are arranged next to one another in a row. In U.S. Pat. No. 5,896,479, use is likewise made of a flat, substantially rectangular ferrule, which is divided into two separable halves, on each of which parallel, V-shaped grooves are provided for receiving the fiber ends. With multiple plug-in connectors of this type, a multiplicity of individual optical fibers can be connected in a confined space. However, disadvantages are the comparatively complex fitting of the fiber ends in the ferrules and a lack of flexibility in use, because the ferrules are in each case made individually for a specific number of fibers. In addition, it is disadvantageous in the case of the solutions with the V-shaped grooves that the fibers cannot be centered very easily in comparison with the prior-art solutions described below (known as the ferrule-sleeve-ferrule systems).
A further solution for multiple plug-in connectors is described in the printed publications cited at the beginning U.S. Pat. No. 5,590,229 and U.S. Pat. No. 5,436,993. In the case of this solution, based on a ferrule-sleeve-ferrule system, each individual fiber of the plug-in connector is inserted into a ferrule of its own. The various ferrulesxe2x80x94individually sprungxe2x80x94are mounted and held in a common carrier body (88, 90 in FIG. 4 of U.S. Pat. No. 5,590,229 and 31 in U.S. Pat. No. 5,436,993). Although in the case of this solution the fitting of the optical fiber ends in the ferrules is much easier than in the aforementioned ferrules with multiple bores, here, too, the flexibility which is advantageous in many cases is lacking, because the carrier bodies are in each case made individually for a specific number of ferrules or fibers.
It is therefore an object of the invention to provide a compact optical plug-in connector for simultaneously connecting a plurality of fiber-optic cables which avoids the disadvantages of the known solutions and is distinguished in particular by easy fitting of the optical fibers and great flexibility in use.
The object is achieved by the features of claims 1 and 13 in their entirety. The essence of the invention is to provide individual sprung ferrules for each of the fibers, to preassemble these sprung ferrules in separate inserts and, for forming a multiple plug-in connector, to accommodate a plurality of these inserts next to one another in a common housing. By the use of individual ferrules, the fitting of the fiber ends is made easier and at the same time a high centering accuracy of the fibers is achieved. The preassembly of the ferrules in separate inserts achieves improved flexibility, because different numbers of inserts can be combined in a simple way to form a plug-in connector. On account of the preassembled inserts, it is possible to dispense with intermediate or parting walls between the inserts in the housing.
A first preferred refinement of the invention is characterized in that the inserts are releasably fastened in the common housing, and that the inserts are fastened in the common housing with snap-in engagement. As a result, simplified mounting and removal of the inserts is made possible, accompanied at the same time by a stable construction of the plug-in connection.
A second preferred refinement of the plug-in connector according to the invention is distinguished by the fact that the inserts respectively have a securing means, preferably consisting of a plastic, in the form of a rectangular frame, which is elongate in the plugging direction, encloses an inner space and in the front side of which an opening is provided for the ferrule and in the rear side of which a through-bore is provided for leading the fiber-optic cable through, that, for the spring-mounting of the ferrule, a spring element, in particular in the form of a helical spring, is mounted in the inner space of the securing means, that the ferrule is inserted into an inner part, which is arranged in the inner space of the securing means and preferably consists of a metal, that the inner part has a guide sleeve for guiding the spring element, and that means which permit an adjustment of the inner part by rotation about its longitudinal axis into different angular positions are provided on the inner part. It is preferred for the adjusting means to comprise an adjusting portion of square cross section, which adjoins the guide sleeve in the front region of the inner part and has a receiving bore for receiving the ferrule, and on which the spring element is supported with its front end. As a result, a stable and adjustable sprung mounting of the ferrule in the insert is achieved with few components.
According to a further refinement, the releasable and snap-engaging securement of the inserts in the housing can be realized particularly simply if, in the case of the securing means, a side wall in each case has a resilient portion with an engagement step arranged on it, and if snap-in openings into which the securing means engage with their engagement steps when the inserts are pushed into the housing are provided in the common housing.
A preferred refinement of the inserts according to the invention is characterized in that the ferrule is inserted into an inner part, which is arranged in the inner space of the securing means and preferably consists of a metal, that the inner part has a guide sleeve for guiding the spring element, that means which permit an adjustment of the inner part by rotation about its longitudinal axis into different angular positions are provided on the inner part, and that the adjusting means comprise an adjusting portion of square cross section, which adjoins the guide sleeve in the front region of the inner part and has a receiving bore for receiving the ferrule, and on which the spring element is supported with its front end.
Further embodiments emerge from the dependent claims.